DESCRIPTION

apt-cache performs a variety of operations on APT's package cache. apt-cache does not
manipulate the state of the system but does provide operations to search and generate
interesting output from the package metadata. The metadata is acquired and updated via the
'update' command of e.g. apt-get, so that it can be outdated if the last update is too
long ago, but in exchange apt-cache works independently of the availability of the
configured sources (e.g. offline).
Unless the -h, or --help option is given, one of the commands below must be present.
gencaches
gencaches creates APT's package cache. This is done implicitly by all commands needing
this cache if it is missing or outdated.
showpkgpkg...
showpkg displays information about the packages listed on the command line. Remaining
arguments are package names. The available versions and reverse dependencies of each
package listed are listed, as well as forward dependencies for each version. Forward
(normal) dependencies are those packages upon which the package in question depends;
reverse dependencies are those packages that depend upon the package in question.
Thus, forward dependencies must be satisfied for a package, but reverse dependencies
need not be. For instance, apt-cacheshowpkglibreadline2 would produce output similar
to the following:
Package: libreadline2
Versions: 2.1-12(/var/state/apt/lists/foo_Packages),
Reverse Depends:
libreadlineg2,libreadline2
libreadline2-altdev,libreadline2
Dependencies:
2.1-12 - libc5 (2 5.4.0-0) ncurses3.0 (0 (null))
Provides:
2.1-12 -
Reverse Provides:
Thus it may be seen that libreadline2, version 2.1-12, depends on libc5 and ncurses3.0
which must be installed for libreadline2 to work. In turn, libreadlineg2 and
libreadline2-altdev depend on libreadline2. If libreadline2 is installed, libc5 and
ncurses3.0 (and ldso) must also be installed; libreadlineg2 and libreadline2-altdev do
not have to be installed. For the specific meaning of the remainder of the output it
is best to consult the apt source code.
stats
stats displays some statistics about the cache. No further arguments are expected.
Statistics reported are:
· Total package names is the number of package names found in the cache.
· Normal packages is the number of regular, ordinary package names; these are
packages that bear a one-to-one correspondence between their names and the names
used by other packages for them in dependencies. The majority of packages fall
into this category.
· Pure virtual packages is the number of packages that exist only as a virtual
package name; that is, packages only "provide" the virtual package name, and no
package actually uses the name. For instance, "mail-transport-agent" in the Debian
system is a pure virtual package; several packages provide "mail-transport-agent",
but there is no package named "mail-transport-agent".
· Single virtual packages is the number of packages with only one package providing
a particular virtual package. For example, in the Debian system, "X11-text-viewer"
is a virtual package, but only one package, xless, provides "X11-text-viewer".
· Mixed virtual packages is the number of packages that either provide a particular
virtual package or have the virtual package name as the package name. For
instance, in the Debian system, "debconf" is both an actual package, and provided
by the debconf-tiny package.
· Missing is the number of package names that were referenced in a dependency but
were not provided by any package. Missing packages may be an evidence if a full
distribution is not accessed, or if a package (real or virtual) has been dropped
from the distribution. Usually they are referenced from Conflicts or Breaks
statements.
· Total distinct versions is the number of package versions found in the cache. If
more than one distribution is being accessed (for instance, "stable" and
"unstable"), this value can be considerably larger than the number of total
package names.
· Total dependencies is the number of dependency relationships claimed by all of the
packages in the cache.
showsrcpkg...
showsrc displays all the source package records that match the given package names.
All versions are shown, as well as all records that declare the name to be a binary
package. Use --only-source to display only source package names.
dump
dump shows a short listing of every package in the cache. It is primarily for
debugging.
dumpavail
dumpavail prints out an available list to stdout. This is suitable for use with
dpkg(1) and is used by the dselect(1) method.
unmet
unmet displays a summary of all unmet dependencies in the package cache.
showpkg...
show performs a function similar to dpkg--print-avail; it displays the package
records for the named packages.
searchregex...
search performs a full text search on all available package lists for the POSIX regex
pattern given, see regex(7). It searches the package names and the descriptions for an
occurrence of the regular expression and prints out the package name and the short
description, including virtual package names. If --full is given then output identical
to show is produced for each matched package, and if --names-only is given then the
long description is not searched, only the package name and provided packages are.
Separate arguments can be used to specify multiple search patterns that are and'ed
together.
dependspkg...
depends shows a listing of each dependency a package has and all the possible other
packages that can fulfill that dependency.
rdependspkg...
rdepends shows a listing of each reverse dependency a package has.
pkgnames [prefix]
This command prints the name of each package APT knows. The optional argument is a
prefix match to filter the name list. The output is suitable for use in a shell tab
complete function and the output is generated extremely quickly. This command is best
used with the --generate option.
Note that a package which APT knows of is not necessarily available to download,
installable or installed, e.g. virtual packages are also listed in the generated list.
dottypkg...
dotty takes a list of packages on the command line and generates output suitable for
use by dotty from the GraphViz[1] package. The result will be a set of nodes and edges
representing the relationships between the packages. By default the given packages
will trace out all dependent packages; this can produce a very large graph. To limit
the output to only the packages listed on the command line, set the
APT::Cache::GivenOnly option.
The resulting nodes will have several shapes; normal packages are boxes, pure virtual
packages are triangles, mixed virtual packages are diamonds, missing packages are
hexagons. Orange boxes mean recursion was stopped (leaf packages), blue lines are
pre-depends, green lines are conflicts.
Caution, dotty cannot graph larger sets of packages.
xvcgpkg...
The same as dotty, only for xvcg from the VCGtool[2].
policy [pkg...]
policy is meant to help debug issues relating to the preferences file. With no
arguments it will print out the priorities of each source. Otherwise it prints out
detailed information about the priority selection of the named package.
madisonpkg...
apt-cache's madison command attempts to mimic the output format and a subset of the
functionality of the Debian archive management tool, madison. It displays available
versions of a package in a tabular format. Unlike the original madison, it can only
display information for the architecture for which APT has retrieved package lists
(APT::Architecture).

OPTIONS

All command line options may be set using the configuration file, the descriptions
indicate the configuration option to set. For boolean options you can override the config
file by using something like -f-,--no-f, -f=no or several other variations.
-p, --pkg-cache
Select the file to store the package cache. The package cache is the primary cache
used by all operations. Configuration Item: Dir::Cache::pkgcache.
-s, --src-cache
Select the file to store the source cache. The source is used only by gencaches and it
stores a parsed version of the package information from remote sources. When building
the package cache the source cache is used to avoid reparsing all of the package
files. Configuration Item: Dir::Cache::srcpkgcache.
-q, --quiet
Quiet; produces output suitable for logging, omitting progress indicators. More q's
will produce more quietness up to a maximum of 2. You can also use -q=# to set the
quietness level, overriding the configuration file. Configuration Item: quiet.
-i, --important
Print only important dependencies; for use with unmet and depends. Causes only Depends
and Pre-Depends relations to be printed. Configuration Item: APT::Cache::Important.
--no-pre-depends, --no-depends, --no-recommends, --no-suggests, --no-conflicts,
--no-breaks, --no-replaces, --no-enhances
Per default the depends and rdepends print all dependencies. This can be tweaked with
these flags which will omit the specified dependency type. Configuration Item:
APT::Cache::ShowDependencyType e.g. APT::Cache::ShowRecommends.
--implicit
Per default depends and rdepends print only dependencies explicitly expressed in the
metadata. With this flag it will also show dependencies implicitly added based on the
encountered data. A Conflicts: foo e.g. expresses implicitly that this package also
conflicts with the package foo from any other architecture. Configuration Item:
APT::Cache::ShowImplicit.
-f, --full
Print full package records when searching. Configuration Item: APT::Cache::ShowFull.
-a, --all-versions
Print full records for all available versions. This is the default; to turn it off,
use --no-all-versions. If --no-all-versions is specified, only the candidate version
will be displayed (the one which would be selected for installation). This option is
only applicable to the show command. Configuration Item: APT::Cache::AllVersions.
-g, --generate
Perform automatic package cache regeneration, rather than use the cache as it is. This
is the default; to turn it off, use --no-generate. Configuration Item:
APT::Cache::Generate.
--names-only, -n
Only search on the package and provided package names, not the long descriptions.
Configuration Item: APT::Cache::NamesOnly.
--all-names
Make pkgnames print all names, including virtual packages and missing dependencies.
Configuration Item: APT::Cache::AllNames.
--recurse
Make depends and rdepends recursive so that all packages mentioned are printed once.
Configuration Item: APT::Cache::RecurseDepends.
--installed
Limit the output of depends and rdepends to packages which are currently installed.
Configuration Item: APT::Cache::Installed.
--with-sourcefilename
Adds the given file as a source for metadata. Can be repeated to add multiple files.
Supported are currently *.deb, *.dsc, *.changes, Sources and Packages files as well as
source package directories. Files are matched based on their name only, not their
content!
Sources and Packages can be compressed in any format apt supports as long as they have
the correct extension. If you need to store multiple of these files in one directory
you can prefix a name of your choice with the last character being an underscore
("_"). Example: my.example_Packages.xz
Note that these sources are treated as trusted (see apt-secure(8)). Configuration
Item: APT::Sources::With.
-h, --help
Show a short usage summary.
-v, --version
Show the program version.
-c, --config-file
Configuration File; Specify a configuration file to use. The program will read the
default configuration file and then this configuration file. If configuration settings
need to be set before the default configuration files are parsed specify a file with
the APT_CONFIG environment variable. See apt.conf(5) for syntax information.
-o, --option
Set a Configuration Option; This will set an arbitrary configuration option. The
syntax is -oFoo::Bar=bar. -o and --option can be used multiple times to set
different options.